SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7db933701ee616468c254643c88894eaa15142d5b302ba9884bc2a46320404b3' 
  AND token = 'Uoyq4ip+0s9CvFEZm/Lswj2JztLGbKapyMlMd7NTyuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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