SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '041f8a5b420529d1afff4cba4d3255e7d2e8773a3752bac54987a8eac48dedae' 
  AND token = '/UUXGrfCYtyD9zL/6ExNY84NQXnqlkpmdYDafKywnT0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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