SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '484444057a2c6fd7d5637a00511403d520b21b9622f167cbaa7912a048ddac51' 
  AND token = 'wqeCIRU9XorAswsYmOIQVTRtTbYPiMueufkkQgFRo30=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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