SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f18529ad1dc7136065509e646606d3b15749876c8210e9ab2ad697a45f817ab9' 
  AND token = 'Gk+3t/lm5X5SvEOHmTD31tfwJeJCAWgVw5qciorVbsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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