SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d506b0bd1a52a6063fda5f247afe657e764f0154fa29968e140e0fe355bb95a' 
  AND token = 'jD+caGqsku+EcgZjCgdKjSgYCXLq6rKTMyq99Jz3bx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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