SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd64e1b0daf247074d31d4f863ab7fc620b77aae310ea4f066e25aabaec4fb525' 
  AND token = 'hXXX6grLtBjpR71UviV0dLE3BHB579KXYj96clzhzQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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