SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b77262a7a418fafaa415a293967d7f3c73c867f432db53af87c4a5d083e203cc' 
  AND token = 'h1v1e/Je1n5sOGr1VwuPgcC9mJQldBL9U+jYURzMrXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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