SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '968f4b7277baec49bdb4b2fa9bb0bad0078b7340a07a490e49c235a1eed99d64' 
  AND token = 'joAZKV0ErMEZHzcb01I3ED24udhHUIAoxC6N83LK/uE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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