SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81250bf5169bab02ee7dcc5556f645f22546ad7a3ec6db006860b82ac32eeaf1' 
  AND token = 'SnwQvLhsyYXsOd9wW3Y+1nXNm5vNdJ2m2rrpePSBTJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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