SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc85a2eb4652ab2c20dabb19444de593992c4f80d12841d1b3724a2e9e556374' 
  AND token = '2r+KS//o+oYv9nFiTr7+QpwFGA1rUKBwYwwAZyvTBzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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