SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd354a572472ea910cb08168adcbb9e6e80d66dfcf47add805409badb555b03c' 
  AND token = '39n/HALKWfBsl3loLGitc+0Ijilt6mDaNT9W2PaY5Mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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