SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82efc8edf561527392c0862e677b1ff8f8fb997494a07f841d34f0291f93a405' 
  AND token = 'JDj/VJdIZ6INnycbvALJQwTCErRJl8IeKeFIgQYL7FY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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