SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2deac4e8bc09d31fd23ed06f50667c6b0dc8c5b9a947d33a42f8f9ac49f2fc09' 
  AND token = 'CxDo6ZWBtrZiSPW1ojAKAi13CUPVvVMog5ioLS1WrxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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