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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c117b9cfeb2b79924102f8e51505d511084c5d8938e8dd638879e08c4b8ae473' 
  AND token = 'T8Rj6DedFKWwNizK4TQqyYavmFo0rSpauk9o+C5/F1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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