SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f574ffc110bd912104e27ee0d2e02c665a5f5cf6282789b63277734eedbf952b' 
  AND token = 'bDJwLum9Th+Ul11+iUTI74jvAiwjslmYnWjN+D67lDs=' 
  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"
    }
  }
}