SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'feb888119139a685cc35fa446f5d6fae3bdab4d2cb62c6d972356842b3bb1a20' 
  AND token = '0hM/QUMc/eXszW33PS+ARYYJvuJ9PpM/mCFg2xnLngs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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