SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '210bc312741b14cd6d34610c89a00a93d2b4f67163e29617a2ac58e43b370557' 
  AND token = 'qpKoD7UhnCQSs9LDLVYRbH6lz2VQpXv/CTipudK/NBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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