SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc9e673f4375423eeea011c32cd4c8637ad61ec362019fe270c8eb27c71840b1' 
  AND token = 'ZexqudlDicsTCtKBUdHjK5qF5K7CClvRiwp+vnZnoFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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