SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa7ff93c58122807363a0fd825ba13f2cc6062a0802046dec147625f2ac908e3' 
  AND token = 'WQNiYLmMxEhbhhdsRntVJiBsoqObCl4UoaOq++ak3T0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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