SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38584b0c1c9547ce3abb5d45ec38df663e4fe7e6725bcbd603a5ba38e1aec15d' 
  AND token = '5Fm0wnrPZi+IUYN2KSmTKpAPGnHDA7Hq23LVVYv9C9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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