SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '82466b7ae994853b993f2cd982eb337e646593d982c496512ed7cc533b0279e1' 
  AND token = 'sJy+ZOM4XfHJvUESnkI8wB67dAIFfo2kzWfHgVbj0M4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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