SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a014526c8cb4383a4725e52b77f76dd496189ec2d74f776be0d8e8222439304f' 
  AND token = 'Xpch6suv9jq3AoBDiAfTWJAAIhKdtWB3LHfAV38knjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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