SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68df08f0be39095bf6a7bf2bec4d6d4383f76aa54412d5ad1466f98ae60bfb63' 
  AND token = 'OCjEk74OvPAl/zWfztLVcqlKUxtPqmweKbFDUr5IGHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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