SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b03ee3620f0efc1922a58ecb9bf1399964ed8daf53ba37ec04a2eeba6dea639a' 
  AND token = 'HLG5X/bz6rvemMp5aYERlbr4rpLyYeJ0ncIfJycsb7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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