SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e861f205e0aac99f965dbbfc9f3414e6754bc20c3b259a72cc36687b1f8926c1' 
  AND token = 'ysQUkmNBD9btzjLCl/fzuFYtwK4aeRYCJ0fpucpBs+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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