SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90c19b4fe59d4291f3bd011d21bbe7874b848aad96ddee17aaf23a3299bcd2f9' 
  AND token = 'WYQTg/Al139vRhk8iussOPXZ1yvTsfEeAmFDdmCHQU8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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