SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58d8c24ecd5a6be2c1f1338d9f495129ec13de4757713a98d74799ae15285f79' 
  AND token = 'jxcqiZqbaHtLB2JaP2x7rFvZoJwXMlBY/ciGtI+2qOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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