SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8aff90cae8444f9507e34bfb2c2609123581b65af1828e6c45243a207831914' 
  AND token = '6rsHTb+a+oQx/2BNV5sW3ZEk7JqaZqGpHal4RXBWhsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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