SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cc441208fa4996d983bbadc02175a42d789b734fd826178e9ca2c532233723d' 
  AND token = 'rUFW217J+6XwlIHyvm3cuhrugRkXLNoguqztwuoBqfE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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