SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fca995ce4faf2160238d8248223de5fc5658961014a111b1ab5259cf0d42bb7' 
  AND token = 'iJh2gs0xZHv0RZilnTCiFrerFPKm9GrR4sfVfbpNjig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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