SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '716e38d76ac66a6e79df78d1600b0a556d4c343cfff40fc706419df00432a1be' 
  AND token = 'OfyAkLDcLZGppDTsOF6IPuycLGhzklPvF/i4xxRjGAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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