SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28117fa9d27ac994e265f42cdc3e8934ca8d866590114393b434b8756f2ddd32' 
  AND token = 'KwIGT5HAXHdU3rF/PLeCSDeQM0O9Q/aI+YY7RD/qSh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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