SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a242fa9787de042416487dc033db3faf23b0693058d4e1f8f34790466c02748b' 
  AND token = 'FqkZH/T35qTnWiozHAdUG9vKR1K2ChDAsJD+sB1RE3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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