SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54b94ae7d1cc794dfc97372d27923c4b5da9e6178e0053908a3b950cbbca30c4' 
  AND token = 'NyMIztMD9H1iq9WUrdiQVfTLT9hhb1sYLlhi6IyFTts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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