SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'dccad23afd1afe916f96e0953eddd19e295589171504e1903e00b70154938db5' 
  AND token = 'VRuoPKklv0nlNb+M6FAqgzhBZ3PD1R8EO/o6uGpNkhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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