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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e243b830c8f267af50172f27e2d28a07c2ca2bef03bcbf26dd7d83278f8377f2' 
  AND token = 'CBABuxnRZx/cGTIwrB7dJ4XEDj0HqQ9rvYuP2Brp+D8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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