SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '25a97596186186df403bbda134145f251a5810f0b255567e1c66e135c09b0cce' 
  AND token = 'weTaA8N5aelT8iktLmuRhfjlH/69AXZE1++e88dE8FQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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