SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e87d2a0d6e61e6755049e61e7183918574c4bfc8b4a73f982cb1fc05fc035169' 
  AND token = 'RrgxNLiUaPR1RZC/iTf9ACSQm8CJvBvhq9sRJjTJ+NE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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