SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '203269b9fe3e645fdd41af26f2c3a4ab71e026af0ea2dd41842f0e5aca3dea3c' 
  AND token = 'VBsPe5P727wZPcJWI/ImfejBW8frhOQn1yRx0V8Md5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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