SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7c50c1126b671b363254906846fee3f27bb3996a03fbeaf73b5e3f16788cffb' 
  AND token = 'KiRLoX9Fdb4h5ZqiWDyGy8ir5HLKZKlfEbuGSNKkolE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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