SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90c0a4af84a679b409ad9ec9154517f5079dbf574d6e7723d6b3b4fbb544a7c2' 
  AND token = 'I8sit/t+D4Zfy4amD3aEesVuFOTz/yRXPNnaJS1Q0ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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