SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab5f819562b3fe97846648aa0abd7b37cbce7a6bfd5e61a91585684dc4b049a5' 
  AND token = 'VCV2kLVCe32bFEtnwbpA84LPjaHoohP4s3pS0CpsXIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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