SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c80528cbd6b1221ba4782ece800b1ea828db77a2c7a29a4b863226b6cd4485e1' 
  AND token = 'CDnd1H/Chm0sEeojTNdmlmqRAsV6Y3vH+SmfHSmIEJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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