SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7454f15b168f4bad4ffadecd3527fdfda038003e2b39eb315efdaecebab5c181' 
  AND token = 'Nh26hXKfdAXTS7bMlRKYBcixwRVEcDaD8se5yRxLVKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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