SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '62848c30f03965cc4d759a2c0b12d79e4c86114f58b8216273b55fd7209b067c' 
  AND token = 'b4mDZGufYHXpizukMVqAs/BN7wDjFUeDab0T/1BVnE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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