SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a5441d916589bee1f684b4f98b4d5671e7c64aa8a12f4c4d9132ef47f8be72d' 
  AND token = 'xGx3SuzvztVsQ/KR/AQ623kAJI8sdCaemXNkjhmUZ7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}