SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9f6273a865f4c1c271a86254327f00ea6499ed0f46791133c2e66acbaf86b6b' 
  AND token = 'cUqfVsv2shhroRbUVB7BJ14yADo5TlxKGXlFPTi6bFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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