SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6ca7e43755a65fa73c46de7a87192615b08942f63de656b90e9555f1076b9b1' 
  AND token = 'IPpJAzv0/CZ4hj1/f8gumTO4YxeAnNLDHSIhmY8EZmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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