SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a27f12ee4419d1fc90e9e06e945b64fa1ffcf2ef85e75f738cce2f8dd18b016' 
  AND token = 'MZCjvAj/Hc6Ow2V93Qlzmqkdk4UoXXVQpw+GJ5YcYpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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