SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c5f63909286fb1966a0b81c4025902161768fed53b8f4bd50292e84abc71c75' 
  AND token = 'yXMYjzMPR/OEEcurYoQGrOVGmR/1F0H9khbXUxPrUZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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