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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e6d4cbdd380929920375748c48c5b5ee66a433e3e923b9f333f58d59052e181' 
  AND token = 'p2yWClBc7/sCbphYrIJWRhkn7WBaPbdQd3/wjtL+l2s=' 
  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"
    }
  }
}