SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf56f53621ed559aed31749fb82411d304cd26ea0210a181a82c7f515d9ad4aa' 
  AND token = 'DMy3e5RdLCG8ujQhKPYuqBhHl4+KahxLJwBDSsPrQM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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