SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2b3ec8cf85768357763296685f8bb684fda99386e4cc27f441fbfa9851f45e2' 
  AND token = 'XFUnF/0s07+6AlTDpFQfNlRFNyPuvWHiogJuZHim1Q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}