SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a230318a0891ba97c90de651a886a974e471ddcfaf92c6293dac665918b6c03b' 
  AND token = 'Knw/rvIrVMOsEQeP5dbGNSkJKN4NgL2yDoH+cGLNWFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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