SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70ec45869d7bf6416e927574d72273fea571a6c9708c4a5a17208942a8750ec7' 
  AND token = 'UIOIr3lSvzbXsA2gCMl7T+QphfZDDC4g5/jp4xjkShQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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