SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb4854ec97802ef92191e709fb60a69808f1b001cf42d8cc5280c9bf4b724c70' 
  AND token = 'wPY2gWYxVokCN37pU/A43LS4w5dtWiFBw6DOQb+EWxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}