SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '625f990077f6e370ee6d1a825875b2a5a0c4246aed10a2dca0f5f0a036d9655c' 
  AND token = '2/ZdB9IA6REOSrFXQGMGWrgryKL4UsrFMRf+nyvYarA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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