SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b4c1016799140569939e9f70b4edc28c1f4185bcbaef62304ed0002036cfe73' 
  AND token = 'BciLd1av0kKFH7+45vqDgu4kbsbXvrRKP2g8Xi7kf34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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