SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6eb1e779b0143f12f8616cf78afb4ea3bec3e0dd515ec9e05a60a6681fdd08be' 
  AND token = 'ewwCCJKIRLSGpNIP3jRfg9oZ++gK0aUoaF4iL0nXAho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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