SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '731ad0651fcfe18f997171a7a87d5978619fa843c02050d0c29a9a6f9bf61ea8' 
  AND token = 'r27DtnA3/eEgyr+1adeWJCtjXg517KhUfcLu2XFBiFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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