SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '739a018d06f84812caa7b0c1a958f3a129869eaa09fe6e98675451beaa86c649' 
  AND token = 'pen6PCJE0r6R2O2bSXUNvJlheOOhKgJwsVjLVoIfa9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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