SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4494411e9e8d55939ef1ad61790ddc8bc5a47b54757c53425fc5b5456daaeb8' 
  AND token = '1+zjkJF/rvGaEz+dmswfzLixeKh4SuhQ2YssBHXrcU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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