SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77f32f6a27effae6393b53480b888533636c5abd42a09797138508ecf94855bf' 
  AND token = 'oeeTCEeQHdo/M0tM+rAqjCL5sSBtOsqX9180OP97Heo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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