SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f650916842eccc3bad37de06eb36d28216f80fc8a6d872cefca2ee783a62458' 
  AND token = 'urmMvldaRZNUU56iIyCYPdeeHLyP+A3X2jbbzdnz4cI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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