SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c64e390cc47d97044194f8108f526f50918fef6b7a222cdf133666eb53ab8f2b' 
  AND token = 'z8HOBw9Mn5PIxS5biC2VEiOG+4Zi+t7wvxymuBsvoCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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