SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8c8a7d5cf6a26901bbd374bcf2b970f94ce9e78ce82337db53ec2ed2e094605' 
  AND token = 'SUSX05IyBfliC3JeKDYcvJ6pSzj+k/8quMwg6kTW0gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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