SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20aa266fa7060f475a26a650850647b790d0602f125d474d24fb309563cf3337' 
  AND token = 'y3CQGWO6fwbBgh36K+5aklqJoAA+EnmKTCPH3Ot0glY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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