SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ffa556cb664308529354a5291ccb3152b35a6d176bf348ca035d619c002e526' 
  AND token = 'hQgt7tvGwcI+If/KbDEmR0kAYCf75lqzRjc7jf4jgzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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