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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1a96414c1a397458436d8c2a2fc5c6feccd94896225f34fe8bcf26aba1bc079' 
  AND token = 'eh/YAY3Mr/Rt1EiJsiyBYs6Se1Hf9BXqjbSojZm6v8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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