SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c639d0892f0dbbe188a5742e20580e1de18ced97657e1c7122876608a8648c01' 
  AND token = 'FWnH1unicglvfTBzW5d4Fhnr2/OL626ylKZUHWDy5hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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