SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d00dc27a5d0ebdea0fe7726a1943f8908640fca886d90642863b0ce5fe876f7' 
  AND token = 'HgFeOi23VSydQORjjnwpxClyfrtupCzdO0tgguGAMsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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