SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7c6a88e50610ee0e2bc4303e14930549981815461384fbb268e73bea121da2c1' 
  AND token = '1N/SHDtDyG0bMEfDVT2J/MhIMRW2cDCgZAzeiuXgqLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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