SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c55881a83ce008ab3dadadb6e05f472788b96abb3376c65d652919f53451d636' 
  AND token = 'tv0NrPZXgtEtoasXBU85hRF2skV9dubGrtPa919AEXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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