SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b04ab5a14a294ae684d7d6095667aa5d3aa2dc5b6ccc5593e145be102c8a89fa' 
  AND token = 'e/pstAXTLbn3pPgmDN9UvMCoCBp9XqXFmtBwnkDYmV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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