SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12fd0790d3ec24a7e598a9105fb0651e0cca92d82df010edba7b512f7778434a' 
  AND token = '7BX0957MK7nenPoMKrGTL7RNPzHWKykQZJzv0CjRln4=' 
  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"
    }
  }
}