SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac01b2fda79ffd4bbc6a2519fc24108dbdef05f007ed57ed45007ad7ea380902' 
  AND token = 'P2i2K/aYuk9+yJ6KsFmYG/R6Rt7tiYHhqiU5K57CziY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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