SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52f5973a0cc209ba98f971f4b681e2b62cb57d3a998cb5c01e14e8baba8e0ae8' 
  AND token = '85F9uRJbAUan1QBwWI/R6LiHqI8oNwX0ECmUYP0Vrwc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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