SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9a7dc59bfb23b43afcffd798eb31e8e23d103418d0a13b1a2a0e627425565cd' 
  AND token = '73nG2QLA6shcNpf5VU6jmin0Z3aFUILD1tcU/SdNLj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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