SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e43f6505dddcf066b28183ed72aec861a75b5e7958fe692aefd0fbc804ecddd9' 
  AND token = 'Ls+wRX7ihuIJExOD1Y7ex3sGLXZ4ep4KneLK7SaArL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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