SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7eac55e242e67faed9896b9752f5eb865b60cea32a7a34c53f62f893edef0eb6' 
  AND token = '6UmFlsLHArcHpDUBKdfOmXheYKoPKIdGW1dl28Gq0R8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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