SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dc35e70b3f29cf425b351944f66f296ddc1de4b7b8c1687e891d69584d05469' 
  AND token = 'p+YYn1p/ubc/XP0MHkvguAMB+qscC/Sl5gBMPjWW+jI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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