SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64c53bb41fac0e659a37f23d021d25ee42c8e9bb850e04f5fb04411a7a185ef3' 
  AND token = '1A8GxYzBEW3YZ1sRlxOkvbvKw7Q+dWRjL1GIhkMBP+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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