SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9ab17d653d0d1cda73a018b15d5b9c532b60d6ab2cac726395a67106a616924' 
  AND token = 'dz6AiXC7qg14KvAThBzp+u0mVIIjy3M6NIqBctkT5O8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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