SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '377ac83e0210f86a9b604d7a7691d01eb3c409e64771a98872a13942787e7cc4' 
  AND token = 'yDuhIBk+0MEkPl0Szni0hgcfoCCvpXjdT1K/0mS7SUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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