SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8039d3725b26b2287e3cc6060964759efc18dce2cf4a95b80149af6e58278b8' 
  AND token = 'IKMJQniCKBmW/KJhAx4PMKgPJkwRz1FdEyTXSKv+bSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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