SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b50fd3786158c8fab70010bcd0c435708d9ff67a5fff3c590142d9c819aebf87' 
  AND token = 'CKzOSjl/2uFwYMX64FW5PZCNYxQnX7sE5XBkT5Qg0vI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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