SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71390ca7cc63071d2b38f2a2e89079ef290325bfe314f5c92bcb1dbdf6c9762f' 
  AND token = 'WS3MhUzQKuJyrmYoVIBSszSlIBnHEsenn9etnJN58hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}